<html>
  <head>
    <style>
      #first {
      width: 200px;
      height: 50px;
      background: blue;
      }
      .center {
      height: 30px;
      width: 30px;
      background: green;
      }
    </style>
  </head>
  <body>
    <div id="first">
    </div>
    <div class="center">
    </div>
  </body>
</html>
